Change default room drawing

room.lua

@@ -7,7 +7,13 @@ local entity = require('entity')
 -- - objects
 -- - edges
 local room = entity:from{
-    background = love.graphics.newImage("res/defaultbg.png"),
+    lines = {
+        {'line', 0, 0, 120, 80},
+        {'line', 320, 0, 200, 80},
+        {'line', 0, 240, 120, 160},
+        {'line', 320, 240, 200, 160},
+        {'fill', 120, 80, 200, 80, 200, 160, 200, 80},
+    },
 }
 
 local from = room.from
@@ -31,7 +37,7 @@ end
 room.mousepressed = window.propagate{'edges', 'objects'}
 
 function room:draw()
-    love.graphics.draw(self.background, 0, 0)
+    self:draw_lines(self.lines)
 
     for i, v in ipairs(self.objects) do
         v:draw()